Fuel Stream Generator Gas Sheath Nozzle Blockage
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Solution Overview
Problem
Existing fuel stream generators in EUV lithographic apparatuses face challenges in delivering fuel droplets of precise size and separation, leading to incomplete vaporization and nozzle blockages, which affect the efficiency and throughput of the apparatus.
Innovation Solution
A fuel stream generator with a nozzle configured to introduce a gas sheath around the fuel stream, constraining its diameter and preventing contact with the nozzle walls, allowing for a larger nozzle diameter that reduces blockage risk while maintaining efficient droplet formation and vaporization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a small nozzle diameter is used to deliver fuel droplets, then droplet size and separation can be controlled, but the nozzle becomes prone to blockages and fuel may not fully vaporize
Solution Approach 1:
A gas sheath (intermediary substance) is introduced between the fuel stream and the nozzle wall to prevent direct contact. The gas sheath acts as a mediator that constrains the fuel stream centrally while protecting it from adhering to the nozzle interior surface, thereby eliminating blockages while maintaining small effective droplet delivery dimensions
Solution Approach 2:
The physical state of the fuel delivery system is changed by introducing a gaseous phase (sheath gas) that modifies the flow dynamics of the liquid fuel. This parameter change allows the fuel to maintain a constrained, centralized flow pattern without direct wall contact, resolving the contradiction between small diameter control and blockage prevention
2Reliability
If a larger nozzle diameter is used to reduce blockage risk, then droplet formation and vaporization efficiency improve, but precise control of droplet size and separation becomes difficult
Solution Approach 1:
The gas sheath serves as a constraining intermediary that effectively reduces the flow path diameter without requiring a physically small nozzle. The sheath gas confines the fuel stream to a narrow central region, achieving precise droplet spacing control while the actual nozzle can have a larger diameter for robustness
Solution Approach 2:
The solution moves from controlling droplet dimensions solely through the nozzle's physical geometry (one-dimensional constraint) to using a gas sheath that provides radial confinement (adding a second dimensional control mechanism). This allows the nozzle to be larger while maintaining precise effective flow dimensions through the sheath's constraining pressure
3Device complexity
If fuel flows directly along the nozzle wall, then the nozzle structure is simple, but blockages occur and vaporization is incomplete
Solution Approach 1:
A gas sheath is introduced as an intermediary layer between the fuel and the nozzle wall. This adds a moderate structural element (gas supply system) that prevents direct fuel-wall contact, thereby eliminating blockages and improving vaporization completeness while maintaining relatively simple overall nozzle geometry
Solution Approach 2:
The solution uses pneumatic principles by introducing a pressurized gas sheath that dynamically constrains the fuel stream. This pneumatic mechanism provides a simple yet effective means to prevent wall contact and blockages without requiring complex mechanical structures or moving parts within the nozzle
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables the generation of fuel droplets with controlled diameter and velocity, enhancing vaporization efficiency and reducing the likelihood of nozzle blockages, thus improving the operational throughput and efficiency of the EUV lithographic apparatus.
Implementation Method 1
the nozzle is provided with a gas inlet configured to provide a sheath of gas that constricts fuel flowing along the nozzle
Implementation Method 2
a plasma formation location arranged to receive fuel droplets from the fuel stream generator and to receive a laser beam configured to vaporize the fuel droplets to form a plasma
Implementation Method 3
The resulting plasma emits output radiation, e.g., EUV radiation, which is collected using a radiation collector
Implementation Method 4
The radiation collector may be a mirrored normal incidence radiation collector, which receives the radiation and focuses the radiation into a beam
Data Source
AI summary
A fuel stream generator comprising a nozzle connected to a fuel reservoir, wherein the nozzle is provided with a gas inlet configured to provide a sheath of gas around fuel flowing along the nozzle is disclosed. Also disclosed are a method of generating fuel droplets and a lithography apparatus incorporating the fuel stream generator.